Bugs

[sawwood]

 I didn't want to high jinks yellowhammer post. We are having low temps here in Mo
 and i need to dry some lumber in our solar kiln. I know that the kiln will not be as
 hot as it will be with the outside temp being only 65.  I worry about bug in our lumber
 as i will not see temps high enough to kill them. I have a two halogen light set so would
 you both or just one to bring the temp up for 24 hours to get read of them? Our kiln is
 the the size of 10 feet long and will hold 500 BF of lumber with two fans. I know i will need
 to cover the solar panel to keep the temp up. I have seen in some of the lumber i use the
 little holes  and know that its not good, Burned all of that load in the burn pile. Any help
 will be great.

 Sawwood

[GeneWengert-WoodDoc]

The dry wood PPB, called the lyctid PPB, likes wood under 18% MC.   The ambrosia PPB likes much wetter wood.    Both make the same size hole.  Long air drying can indeed get the dry wood PPB.   Make sure any stickers or 4x4s are also sterilized.  Oftentimes a small heating chamber is cheaper and more effective than using a solar kiln.

The dry wood PPB takes 9 months to a year from the time eggs were laid until the holes appear.  So, six months air drying will not have the lyctid PPB evident.  Plus after six months, the wood can be too wet still.

[caveman]

We pulled another load out of our hot box this morning.  It was 152° yesterday afternoon when I unplugged it.  Five hours later it was still above 140°.  Three halogen lights take about 24-30 hours to get the temp up to 150° and we have been holding it there for 24-30 hours and then unplugging the lights and letting the temperature come down slowly over the next 18-24 hours.  Two 500 watt lights would not provide enough heat for our small box.  We even added another 250 watt heat lamp to supplement the three halogens this time to bring them up to temperature and unplugged it when it reached 150°.  We do have a few leaks so it is not completely efficient.  That was one of the things we had planned on working on this week but we are using it to store dry, sterilized lumber now.  

We have 4" of styrofoam insulating for the walls and 8-9" on the top.  There are also a couple of inches of insulation under the floor.  We have considered making a shelf in the solar kiln to hold foam panels so that we could add auxiliary heat to sterilize but the way our kiln is currently arranged it would be cumbersome and would require 6-8 500 watt lights, most likely.

[caveman]

I sawed some cedar cookies last weekend that had termites in the sapwood.  Sunday afternoon the cookies were sticker stacked in the solar kiln.  Today when I inspected them, there were a lot of dead termites.  

 

[flatrock58]

I made my solar kiln with a separate chamber that can be shut off to sterilize.  It is 8'w x 8't x 14' long.  I usually let the sun heat the kiln up to around 120 degf.  Then I close off the solar collector section and run 5 halogen lights to bring up the temperature to 150 degf.  Last week when the temperature was dropping to 35 degf at night it took about 14 hours to get it up to temperature.  After it is at 150 degf I cut back to 3 or 4 light to maintain it.

 

[Don P]

I doubt there is an easy answer to "how many lights", there are too many heat loss variables. In caveman's pretty well insulated pretty tight chamber he is getting those results, but you'll be working with probably 20 degrees or so more difference inside to out, that's going to take more heat. You'll have enough heat when you can get the wood core to 150 and hold it there. In anything more long haul than a load or two, draftstopping and insulation is gonna be cheaper than throwing energy at it. From my experience with the DH as the temperature differential gets greater draftstopping is more and more important. As the temp difference goes up I find new leaks pouring out the heat, and another can of Great Stuff gets added to the decor :D.

[caveman]

In caveman's pretty well insulated pretty tight chamber he is getting those results

DonP,
The last time I ran our sterilizing box, I left three lights plugged in too long (I did not trust my cheap thermometer) and melted some of the 4" foam.  John and I did not have any sawing jobs last Saturday so we pulled the roof off and added a better fitting insulated top panel and cut new panels for the front to replace the ones I deformed with excess heat.  Our thermometer, which is digital, shuts down somewhere around 160 F.

Flatrock, I really like the looks of your kiln.  Our next one will hopefully be able to dry using solar and sterilize with electrical heat (lights).  We will have to go back to the drawing board before we start on it.